Ever wonder what those black bars across your business letters are for? Together, those 65 black bars are called the Intelligent Mail Barcode (or, "IMB"). First announced in 2003, the IMB came into use in 2006 for United States mail and served as a way to increase the amount of information carried on letters and mail flats, expanding the tracking capabilities for mail carriers. Your IMB is divided into four parts: Ascender (A), Full (F), Tracker (T), and the Descender (D). This video teaches how to read and decode the IMB on a letter and the two main benefits of knowing how to decode an IMB: Free address correction services (returns being free) and the ability to track each individual piece of mail.

Note: The Intelligent Mail Barcode is many times abbreviated as "IMB", but is at time referred to as "OneCode" or "4-State Barcode".